Our ability to accurately assess human health risks from environmental and occupational exposures to potential carcinogens is presently limited due to the use of default assumptions used in making extrapolations from in vitro and laboratory animal data to humans. This degree of uncertainty can be reduced by incorporating mechanistic information relating to the process of tumor development into biologically based risk assessment models. Among the factors that can influence tumor development in humans and animals are genetic factors that can act as determinants of cancer susceptibility. How to incorporate these genetic susceptibility factors into the risk assessment process in order to characterize human risk is the subject of this conference. Recent advances in genetics have increased our understanding of the molecular basis of susceptibility to carcinogenesis in animals and humans. This information has impacted our ability to recognize subpopulations which are at increased risk for cancer development from the general human population exposed occupationally and environmentally to carcinogens. Both intrinsic genetic factors and extrinsic modifiers of human cancer risk are now being identified which will impact risk assessment in the future. In addition, the availability of genetically modified animal models in which susceptibility to tumor development can he modulated under a variety of experimental conditions raise new questions that must be addressed regarding the extrapolation of cancer bioassay data generated in these models to human risk assessment. The goal of this conference will be to provide an understanding of genetic factors that can influence cancer susceptibility and the role of these factors as determinants of human cancer risk. Sessions will focus on susceptibility factors that are the targets of chemical carcinogens, intrinsic factors that modify cancer risk and biomonitoring and extrinsic risk modification. This conference is the eighth international meeting in a series covering research and contemporary issues on carcinogenesis and risk assessment. Each session will be chaired by an expert in the field and will have several invited speakers and time for discussion. Other contributed abstracts will be presented as posters. Invited speakers are leaders in specific areas of cancer research, epidemiology and risk assessment who can facilitate integration of these diverse fields to address the impact that genetic and susceptibility factors will have on risk assessment in the future. The proceedings of this meeting will be published as a monograph in a series published by Wiley Liss.